Brush-tailed bettong description

As its name suggests, the most distinctive feature of the highly threatened brush-tailed bettong (Bettongia penicillata) is the black crest of fur that extends along the end of its tail (5). The tail is prehensile and is used to grasp and carry nesting material such as grass (7).

Similar in appearance to a small kangaroo, the brush-tailed bettong has dense grey-brown fur on its back and pale white-brown underparts, and it typically stands and hops on muscular hind limbs while holding its shorter forearms close to its belly. Its eyes are relatively large and the small ears are round (6).

There are two subspecies of brush-tailed bettong; Bettongia penicillata penicillata and Bettongia penicillata ogilbyi, although B. p. penicillata may now be extinct (1).

Related species

Brush-tailed bettong biology

This nocturnalmarsupial is primarily a solitary animal, with individuals socialising only for courtship, mating and rearing young (5)(9). The brush-tailed bettong breeds throughout the year and females produce a maximum of three young each year. A single young is usually born, (although twins have been observed), after a gestation period of around 21 days (10). Like all marsupials, the young are highly undeveloped at birth, but they are able to crawl up the mother’s stomach to her pouch where they remain for approximately the next 90 days, feeding on milk and developing within the protected pouch (5)(10). Female brush-tailed bettongs reach maturity at about six months of age, and this species is thought to live for four to six years in the wild (10).

Interestingly, underground fungi form the bulk of the brush-tailed bettong’s diet (11), which it locates using its keen sense of smell and digs up with its robust front claws (5). The brush-tailed bettong has a special stomach containing abundant bacteria, to enable the breakdown of the fungi and the release of digestible nutrients (5). Fungal spores are not digested and are deposited in faeces in a new location, thus creating a mutually beneficial relationship. Fungi are also beneficial to trees as they assist with nutrient uptake from the soil, so in dispersing the fungi, the brush-tailed bettong is actually keeping Australia’s forests healthy (5). As well as fungi, the brush-tailed bettong feeds on bulbs, tubers, seeds, and insects (11). It is believed to rarely drink water in the wild and instead extracts all the water it needs from its diet (12).

Brush-tailed bettong range

The brush-tailed bettong occupies a small fraction of its historical range, having formerly inhabited over 60 percent of Australia (2)(7). Today, original populations of the brush-tailed bettong exist at Perup Nature Reserve, Tutanning Nature Reserve and Dryandra Woodland in south-west Australia, and introductions have occurred in other sites within Western Australia, South Australia and New South Wales (1).

Species with a similar range

Brush-tailed bettong habitat

The brush-tailed bettong is found in a variety of habitats, from temperate forests to desert grassland (1), but it most commonly occurs in open forests and woodlands which have a low clumped understorey of tussock grasses or woody shrubland (8). It makes its nests from tussocks of grass (7).

Brush-tailed bettong status

Brush-tailed bettong threats

The once abundant brush-tailed bettong has been impacted over the years by numerous threats. Historically, this species was considered a pest and over three million were killed between 1880 and 1920 for bounty money (7). The introduction of predators and competitors such as foxes, cats, rats and rabbits, combined with habitat reduction from farming and altered burning regimes have all had detrimental effects on the species (2).

The translocated populations may also suffer from inbreeding; for example the Wedge Island population was founded from only four individuals (1).

The brush-tailed bettong’s downward population trend (1) will also affect surrounding habitat because of the dependence of fungi on the bettong for dispersal (5).

Brush-tailed bettong conservation

The Critically Endangered brush-tailed bettong is reliant on the monitoring and reduction of fox populations as well as careful habitat management for its survival (7). Research is currently underway to identify possible new translocation sites (1), and an investigation is being carried out by the Woylie Conservation Research Project to discover why all large brush-tailed bettong populations across Australia dramatically declined in 2001. Predation, disease and food availability are the main areas under investigation (1), and hopefully the findings will enable the prevention of further declines in the future.

Glossary

The breeding of closely related individuals. An inbred population usually has less genetic variability and this is generally disadvantageous for its long-term survival and success.

Marsupial

A diverse group of mammals characterised by their reproduction, in which gestation is very short, and the female typically has a pouch (marsupium) in which the young are raised. When born, the tiny young crawls to the mother’s teats, where it attaches and stays for a variable amount of time, whilst it continues to develop. Marsupials also differ from placental mammals in their dentition.

Nocturnal

Active at night.

Prehensile

Capable of grasping.

Spores

Microscopic particles involved in both dispersal and reproduction. They comprise a single or group of unspecialised cells and do not contain an embryo, as do seeds.

Subspecies

A population usually restricted to a geographical area that differs from other populations of the same species, but not to the extent of being classified as a separate species.

Translocation

When individual living organisms from one area are transferred and released or planted in another area.

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